Stiffener for boots and shoes



Aug. 2, 1927.

LPREBLE STIFFENER FOR BOOTS AND SHOES Filed March 18, 1924 Patented'Aug 2, 1927..

UNITED STATES PATENT OFF-ICE.

GEORGE L. PREBLE, OF LYNN, MASSACHUSETTS, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO PREBLE BOX TOE 00., 0F LYNN, MASSACHUSETTS, A CORPORA- TION OF MASSACHUSETTS.

STIFFENER FOR BOOTS AND SHOES.

application filed March 18, 1924. Serial No. 700,009.

Heretofore it has beenprop-osed to roll a thick gummy coating or spreading mixture upon a ing box-toes for boots and shoes. I have discovered that markedly superior results can be secured by thoroughl impregnating a fibrous base with a liqui mixture contained in a volatile carrier, partially evaporating the carrier, compacting the mass of fibers, and finally drying. Thus instead of producing a superficial coating by rolling I completely fill the interstices by impregnation and preferaby scrape off the superficial excess.

Any fabric or felted base may be e1nployed, depending upon the type of boot and shoe for which the stiffeners are intended, but I have secured best results with a fabric sheet (such as burlap for mens box-toes and sheeting for womens box-toes) having anchored thereto a mass of loose fibers such as jute fibers. The fibers may be anchored in various ways but preferably by punching the fibers through the fabric at recurrent intervals.

In general the treatment of the base comprises impregnating with a fluid mixture containing a suitable compound or cone pounds of cellulose or its polymers partially or completely dissolved in a suitable solvent, preferably With the addition of a comminuted fluid-retaining substance or an adhesive sacchai'ose or both, saturating a fibrous base material with said mixture, shaping the material so treated and permitting the same i to harden, accompaniedby evaporation of the solvent. The cellulosic compound used may be any appropriate derivative or compound of cellulose or a polymeric form of cellulose, characterized by ability to form a crystalloidal or colloidal solution in a suitable solvent and to stiflen or harden a base material saturated therewith upon subsequent evaporation of the solvent. For some purposes, where the adhesive properties of the molding composition are to be prolonged during the drying and hardening operations,

it has been found advantageous to add to the impregnating fluid a saccharose' or polysaccharose, such as sugar, dextrine, etc. The interaction or interrelation between such addition and the other ingredient or ingredients is not clear but it is observed that when this addition is made to the impregnating fibrous base for the purpose of makfluid a larger amount of the solvent or of the comminuted material maybe added thereto Without decreasing the saturation properties of the mixture and its adhesive propensities with respect to other materials which it may be desirable to incorporate With the molded article are enhanced.

The comminuted substance used may or may not'be cementitious, but is of such character as to cling to the fibers-0f the base and to form capillary voids, adapted to induce absorption of the fluid therein and to retain a relatively large proportion of it within and upon the base material used.

The saturation of the base material is accoinplishedin any convenient manner as by simply immersing it in the fluid, when rapid and complete impregnation of the material takes'place. The superficial excess is pref-' erably removed to provide the desired thickness and thetreated material may be compressed and compacted into a thin dense sheet, or may be molded to the desired form by any convenient means with or without pressure as the character of the stiffener or the. purpose for which it is intended 'may determine. The shaping operation may be effected after impregnation and before hardening, as described, or the material may be allowed to harden before being shaped and subsequently softened for the shaping operation, after which the material is allowed to thoroughly dry and harden in its final form.

While the ingredients of the impregnating composition may be widely varied for different types of boots and shoes the following proportions, which are well adapted to the principal uses, will serve as examples:

lVomens box-toes: .16 vols. liquid celluloid (20- B.), 4 vols. comminuted asbestos, 1 vol. dry dextrine, 12 vols. alcohol.

Mens box-toes: 2O vols. liquid celluloid (20 B.), 4 gels. comminuted asbestos, 4 vols. comminuted plaster of Paris, 1 vol. dextrine, 16 vols. alcohol. 3

The celluloid, when incorporated in the base, renders the product stiff but elastic, and can readily be resoftened. by Wetting with alcohol for the purpose of reshaping the product. The comminuted absorptive substance facilitates the impregnation of the base, apparently by helping to hold the celluoid solution in the base until it dries since a solution of this composition evidences much less tendency to flow out of the base after impregnation and'beforedryingithan does a'celluloid solution containing, no such substance. The admixture of absorptive suba stance also reduces the amount of celluloid requiredto give the desired degree of stiffness and body to the treated base.

Plaster of Paris also adds stiffness if employed in unhydrated 'form and if the im- 1H pregnating solution contains some water in addition to the celluloid solvent. The plaster of Paris also reduces the flammability of the resulting product and if used in sufiicient proportion it renders the product firela proof. Asbestos also reducesthe flammability of the product and owing to its fibrous character, even in comminuted form, it renders the product smoother and tougher.

The ratio between the asbestos and plas- 2 ter of Paris may be adjusted to any point at or between the two extreme limits depending upon the particular use. Likewise .the ratio between the cellulosic material and the absorptive substance may be widely va- 25.ried to suit the requirements of different bases and different products. For example, by using all plaster of Paris as the absorptive substance and using asmuch plaster of Paris as liquid celluloid (by V010) the stiffeners are substantially fire-proo Fig. l-is a sectional view of the stiffener material in which 1 represents the threads of the fabric and 2 the fibers, the cellulosic matrix being represented by cross-hatching and the comminuted absorptive substance by stipplin Fig. 2 illiistrates one application of the invention in which 3 is a last, 4. an insole, 5 a welt, 6 the shoe lining, 7 the box-toe and 8 the upper. If the box-toe has been dried prior tothe lasting operation it is rewet by dipping in alcohol or other suitable softener prior toits application to thelast.

An outstandin feature of the product so obtained is the large amount of cellulosic material which is incorporated therewith both within the interstices of the fabric and upon the surfaces. Such concentration producesa stiff and strong article after it has been allowed to harden, even when thin fabrics, are used or when a thick fabric is impregnated and compacted to narrow dimensions.

The saturated fabric produced in this manner possesses an appreciable degree of adhesiveness while wet, but upon drying this rapidly diminishes. By the addition of -saccharose, such as sugar or dextrine, to the impregnating fluid, it is found that its adhesive properties are prolonged and that surfaces to which the sheets may be applied or other materials. incorporated with the mixture, are permanently retained thereby. While the celluloid containedin an article made according to the process described is intrinsically flammable, the finished article itself' will be found to be appreciably less inflammable regardless of the combustible or Y non-combustible condition of the fibrous as ignition is conmaterial used, and so fag to relatively high cerned may be subjecte temperatures with impunity. Thestructure formed by the comminuted substance -protects the celluloid in this regard and also imparts strength and rigidity to the whole.

to the additionfof the comminuted substanGe are required and wherethe adliesive properties of the-saccharose is unnecessary, impregnation may be effected with the cellulosic solutionalone. Other variations andmodifications of the invention may, and ordinarily will be made in practice to adapt it to the numerous purposes for which it is clearly appropriate, and to modify or control theing a fibrous sheet, an interlacing structure of a comminuted substance interspersed among the fibers thereof, and a matrix of a cellulose ester and a saccharose in the interstices between said fibers.

3. Stiffeners for boots and shoes comprising a fibrous sheet, powdered asbestos intersp ersed among the'fibers thereof, and a matrix of cellulosic' compound susceptible of softening with an organic solvent in the interstices between said fibers and asbestos.

4:. Stiffeners for boots and shoes compris 1 ing a fabric sheet, ,hydrated powdered asbestos interspersedamong the fibers thereof, and a matrix of a cellulose ester in the interstices between said fibers and powdered asbestos.

Signed by this 5th day of March, 1924.

meat Boston,- Massachusetts,

- GEORGE L. PREBLE. V

75 In some instances, where neither fiammability nor the other properties incidental. I 

